The move should awe but not shock. Amazon was already pushing into the $800 billion grocery business via its Amazon Fresh delivery business, which competes with the likes of Instacart, FreshDirect, and Google Express. So far these services have made inroads mostly in the nation’s densest cities, including New York and San Francisco.

What Amazon brings is the world’s largest online sales portal and its mastery of the home-delivery business. Scale, meet scale. Logistics, meet logistics. Loyal customer base, meet loyal customer base. If you’re in the grocery business and your name is not Amazon or Whole Foods, today is not a good day for you.

But Amazon is also chasing something even larger here. Its move into groceries isn’t just about adding a new territory to its online retail empire. It’s about dominance, comprehensiveness, and the pursuit of monopoly.

Adding groceries to its repertoire gets Amazon that much closer to being a one-stop destination for everything you buy. It gets customers visiting Amazon.com not just occasionally, but several times a week, every week. It reinforces the behavior by which customers search for things to buy on Amazon.com, rather than on a search engine like Google. It builds Amazon’s two-hour delivery business, which it sees as crucial to its future.